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United States Patent |
5,650,227
|
Starzewski
|
July 22, 1997
|
Polyacetylene-containing mouldings
Abstract
Mouldings made from polyacetylene-containing polymer products comprising
poly-acetylene and a polymer other than polyacetylene are distinguished by
improved stability of their optical and electrical properties in air when
they have a protective coating of a silicate.
Inventors:
|
Starzewski; Karl-Heinz Aleksander Ostoja (Bad Vilbel, DE)
|
Assignee:
|
AGFA-Gevaert Aktiengesellschaft (Leverkusen, DE)
|
Appl. No.:
|
516676 |
Filed:
|
August 18, 1995 |
Foreign Application Priority Data
| Aug 25, 1994[DE] | 44 30 097.2 |
Current U.S. Class: |
428/341; 428/427; 428/428; 428/429; 428/441; 428/446; 428/447; 428/448; 428/453 |
Intern'l Class: |
B32B 027/28; C08J 007/06; C08L 049/00; C09D 001/02 |
Field of Search: |
428/341,427,428,429,446,447,448,453,441
|
References Cited
U.S. Patent Documents
5049427 | Sep., 1991 | Starzeski et al. | 428/40.
|
Foreign Patent Documents |
0311432 | Apr., 1989 | EP.
| |
0374626 | Jun., 1990 | EP.
| |
Other References
Database WPI, AN 85-313746, abstract of JP 60-218 661 and Derwent Abstract
of said patent, Nov. 1, 1985.
|
Primary Examiner: Nakarani; D. S.
Attorney, Agent or Firm: Sprung Horn Kramer & Woods
Claims
What is claimed is:
1. A moulding made from a polyacetylene-containing polymer product
comprising polyacetylene and a solvent soluble polymer other than
polyacetylene which moulding has a protective coating of a sodium silicate
or a potassium silicate, said protective coating of silicate being
produced by applying aqueous solution of sodium water glass or potassium
water glass and drying it.
2. The moulding of claim 1, wherein the polyacetylene makes up from 0.1 to
99% by weight of the total amount of polyacetylene and the polymer other
than polyacetylene.
3. The moulding of claim 1, wherein the polyacetylene makes up from 1 to
50% by weight of the total amount of polyacetylene and the polymer other
than polyacetylene.
4. The mouldings of claim 1, wherein the protective coating is from 50 mg
to 2 g of a sodium silicate or a potassium silicate per m.sup.2 of surface
of the moulding.
5. The moulding of claim 1, wherein at least one further dried layer is
formed between the moulding of polyacetylene-containing polymer product
and the silicate protective coating by immersing the moulding into a
solution of tetramethoxysilane, tetraethoxysilane, boric acid or borax and
drying it before forming said protective coating.
Description
BACKGROUND OF THE INVENTION
The invention relates to polyacetylene-containing polymer products which
are distinguished by improved stability to air and in particular oxygen.
Polyacetylene-containing polymer products are disclosed in U.S. Pat. No.
4,769,422. They are suitable, for example, as organic-based electrical
conductors and semiconductors. In contrast to pure polyacetylene, they can
easily be converted into mouldings, for example films or fibres. They are
more stable than pure polyacetylene. However, they are sensitive to oxygen
at elevated temperature.
Their preparation is described, for example, in U.S. Pat. No. 4,769,422, in
which acetylene is polymerized in organic solution of at least one polymer
other than polyacetylene and in the presence of certain nickel(0)
complexes. The resultant polyacetylene-containing polymer product can
contain from 0.1 to 99% by weight, preferably from 1 to 50% by weight of
polyacetylene.
SUMMARY OF THE INVENTION
The present invention refers to mouldings made from a
polyacetylene-containing polymer product comprising polyacetylene and a
polymer other than polyacetylene which has a protective coating of
silicate.
DETAILED DESCRIPTION OF THE INVENTION
The polymer other than polyacetylene can be any soluble polymer, for
example polystyrene, polycarbonate, polyvinyl chloride, polychloroprene,
polyether, polyacrylonitrile, polyvinylpyrrolidone, polyisoprene,
polyvinyl alcohol, cellulose derivatives, for example methylcellulose and
copolymers, such as acrylonitrile copolymers, butadiene-acrylonitrile
copolymers, which may be hydrogenated, or acrylonitrile(meth)acrylate
copolymers. The solvents employed are the solvents which are suitable for
said polymers.
Preference is given to polymers containing polar groups, for example
halogen atoms, nitrile groups, hydroxyl groups, acetyl groups or carbonate
groups, for example polyvinyl chloride, polyvinyl alcohol,
polyvinylbutyral, polyacrylonitrile and acrylonitrile-containing
copolymers, and polyvinylpyrrolidone, polyvinylcarbazole and
methylcellulose.
Preferred solvents are polar aprotic substances, for example
dimethylformamide and dimethyl sulphoxide.
On a macroscopic level, the polyacetylene-containing polymer products
exhibit either a heterogeneous or a homogeneous distribution of
polyacetylene in the polymer matrix. The heterogeneous distribution is
evident from discrete black particles of polyacetylene in the polymer
matrix, but in highly disperse distribution. The homogeneous distribution
is evident from a continuous yellow-brown, red to deep blue colouration of
the polymer product.
All polyacetylene-containing polymer products can be converted into
mouldings, for example filaments or films, in the conventional manner
without loss of their optical and electrical properties. The polyacetylene
can also be in oriented form here.
The electrical properties do not change on extended storage.
The polyacetylene can be doped in a conventional manner, for example with
iodine. The doping increases the electrical conductivity, if desired, by
up to about ten powers of ten, making the products suitable for a broad
range of applications from nonconductors via semiconductors to electrical
conductors. The formal degree of doping is obtained from the increase in
weight caused by iodination.
In accordance with the invention, the mouldings of the
polyacetylene-containing polymer products are provided with a silicate
coating. This is achieved, in particular, by immersing said mouldings into
an aqueous solution of sodium water glass or potassium water glass and
subsequently drying the coated mouldings. Even extremely thin coatings
result in excellent stabilization of the polyacetylene to oxygen, for
example even coatings of about 1 .mu.m. From 50 mg to 2 g of water glass
(solid) are preferably required to stabilize 1 m.sup.2 of moulding
surface. The moulding surface can preferably have been treated in advance
with a silane or a borate, this treatment being carried out in such small
amounts that the increase in weight is virtually unmeasurable.
This pretreatment is also achieved by briefly immersing the moulding into
the solution of a silane or a borate and drying the coated moulding, it
also being possible to immerse the moulding into the pure compound in the
case of liquid silanes.
Examples of suitable silanes are tetramethoxysilane and tetraethoxysilane.
Suitable borates are boric acid and borax.
The stabilizing effect of the silicate coating can be demonstrated in a
heat test carried out in air.
To this end, thin transparent coatings of matrix polyacetylenes are
produced and their absorption spectra are measured before and after
heating.
EXAMPLES
Example 1
(PVPPAC)
5 g of polyvinylpyrrolidone (PVP) were dissolved under an argon protective
gas atmosphere in 95 g of dry dimethylformamide (DMF) for 30 minutes at
about 60.degree. C. with magnetic stirring in a 250 ml 4-necked flask
which had been dried by heating and which was fitted with an internal
thermometer, argon and acetylene gas inlet and excess pressure valve. At
60.degree. C., 0.5 mmol of catalyst [NiPh(Ph.sub.2 PCHCPhO)(i-Pr.sub.3
PCHPh)] dissolved in 3 ml of DMF were then injected and stirred in for 1
minute (Ph=phenyl; i-Pr=isopropyl). Acetylene gas was then passed through
the solution in a rapid stream for 30 seconds, the solution becoming a
blue-black colour. Unreacted acetylene was expelled by a vigorous stream
of argon.
The PVPPAC solution was diluted with DMF in the ratio 1:1. Glass specimen
slides were coated by vertical dipping into this solution and drying in
air, and the light absorption in the visible wavelength range was
measured. Further measurements were carried out after heating at
90.degree. C. in air. The absorbance drops after this heating, and the
absorption maximum shifts to shorter wavelength. The colour of the clear
coating changes from blue to reddish.
______________________________________
t (90.degree. C.)
E.sup.max
.lambda..sup.max
______________________________________
0 min 2.83 642 nm
60 min 2.36 588 nm
120 min 2.09 562 nm
______________________________________
EXAMPLE 2
(PVPPAC, silicate)
The procedure was as in Example 1, but after the coating had been produced,
the slide was first dipped in tetraethoxysilane for about 2 minutes, dried
and then dipped briefly into aqueous sodium silicate solution and dried.
The absorption spectrum was now unchanged after the 2-hour heat treatment.
EXAMPLE 3
(Me-CELPAC)
The procedure was as in Example 1, but 2.5 g of methylcellulose were
dissolved in 97.5 g of DMF over the course of 1 hour and 0.25 mmol of
catalyst were employed. The blue-black Me-CELPAC solution was used
directly for the dip coating, i.e. without further dilution. After heating
at 90.degree. C. for 2 hours, the absorbance had dropped from 3.89 to 2.46
and the absorption maximum had shifted from 707 nm to 601 nm.
EXAMPLE 4
(Me-CELPAC, silicate)
A dip-coated glass plate from Example 3 was aftertreated as described in
Example 2. The absorption spectrum did not change in the 4-hour 90.degree.
C. heat test.
EXAMPLE 5
(PANPAC)
The procedure was as in Example 3, but the matrix polymer used was
polyacrylonitrile. The blue-black PANPAC reaction solution was used
directly for the dip coating.
After heating at 90.degree. C. for 4 hours, the absorbance of the glass
plate coated on both sides with PANPAC had dropped from 1.95 to 1.32; the
absorption maximum had shifted from 663 nm to 550 nm and the colour had
changed from blue to reddish.
EXAMPLE 6
(PANPAC, silicate)
A dip-coated glass plate from Example 5 was after-treated as described in
Example 2. The absorption spectrum did not change in the 4-hour heat test.
Accordingly, the colour of the coating remained blue.
EXAMPLE 7
(PANPAC, silicate)
A sample produced as described in Example 6 was kept at 90.degree. C. for
10 days, during which the colour and spectrum remained unchanged.
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